Final answer:
A close whisper is 1,000,000 times more intense than the threshold of hearing and 100,000 times more intense than normal breathing.
Step-by-step explanation:
(a) The intensity of a close whisper is about 60 dB, while the threshold of hearing is around 0 dB. To determine the difference in intensity, we can use the formula:
Intensity difference = 10^(dB difference/10)
For a close whisper, the intensity difference compared to the threshold of hearing would be:
Intensity difference = 10^(60/10) = 10^6 = 1,000,000 times more intense
(b) Normal breathing has an intensity of around 10 dB, so the intensity difference compared to a close whisper would be:
Intensity difference = 10^(60-10/10) = 10^5 = 100,000 times more intense